Altec Lansing inMotion iM4

At a Glance

Altec Lansing's $180 inMotion iM3 is one of our favorite portable speaker systems for the iPod due to it's impressive combination of small size, good sound quality, and useful features. However, for many consumers -- especially those who don't care about advanced features -- $180 is a high price to pay for what is essentially just a way to listen to your iPod on the go, so competing products for $100 or less have been selling well. Altec Lansing has responded to these lower-cost competitors with the new inMotion iM4.

Despite the higher model number, the iM4 is actually a "lite" version of the iM3. The company has stripped the iM3 of all but the essential listen-on-the-go functionality, given it a less-iPod-specific appearance (black and white instead of white and aluminum), and dropped the price to $100, a sweet spot in the consumer market. The result is an excellent portable speaker system that sounds good and offers a bit more flexibility in terms of compatible sources. Because the iM4 is such a clear derivative of the iM3, we're going to be reviewing it in relation to the iM3; see our full review at http://playlistmag.com/reviews/2004/10/alteclansingim3/index.php for a point of reference.

The obvious advantage of the iM4 over the iM3 is that it looks quite at home when used with portable players other than the iPod. When the unit unfolds, it presents a 5" x 5.5", non-slip center platform that can accommodate anything from an iPod shuffle to a portable CD/DVD player. Whatever source you use, it connects via the player's headphone jack rather than the iPod dock connector used by the iM3. In fact, the iM4 provides a spring-loaded, retractable 1/8" cable -- pull it out when in use, and when you're finished, press a button and the cable automatically retracts into the body of the system. (If you've got two sources, the iM4 also provides a second input in the rear, just like its big sibling.)

Because the two systems use the same speaker drivers in similar configurations, you might expect them to sound the same, and for the most part you'd be correct. However, the enclosures themselves are slightly different, and slight differences in speaker enclosures are known to affect the resulting sound. In our unscientific comparisons, the two systems sound very similar, with the iM4 possibly providing a tiny bit more warmth in the midrange and upper bass. That being said, you'd never notice the difference without the type of direct A/B testing we did.

We also like the slightly different folding design of the iM4 -- the speakers rotate freely up and down, allowing you to position them at any angle, all the way up to flat (180 degrees). Since optimal sound quality is obtained when your ears are in the same plane as the speaker drivers, the iM4 allow you to get the perfect angle, even when the system is sitting on a desk immediately in front of you.

On the other hand, the iM4 is clearly not as feature-rich as the iM3. For starters, it has no wireless remote control. And because it doesn't have an iPod dock connector, it doesn't charge your iPod when used with AC power, and can't sync your iPod with your computer. (Connecting via the headphone jack also means that you need to manually find the right balance between the iPod's volume and that of the iM4.) Finally, the iM4 is almost twice as heavy as the iM3, at 28 ounces vs. 15 ounces, and, to ensure room for a portable CD player on the center platform, is a good deal larger than the iM3: 10.5"W x 5.3"H x 1.0"D vs. 8"W x 5.5"H x 1.1"D, respectively, when closed. (The difference is even more noticeable when the units are open, as the iM3 is only 4.5" tall when unfolded.)

Overall, which unit you prefer depends largely on whether you want or need the iM3's docking functionality and remote control. If not, go for the inMotion iM4; you'll get an excellent portable speaker system and save a good chunk of change in the process.--Dan Frakes